This invention relates to weather stripping for windows and doors, particularly windows of the casement or awning type, principally for domestic use.
The conventional form of weather stripping around casement and awning windows or doors is a thin flexible sheet of copper or aluminum. These foil weather strips are located between the door jamb and the outside peripheral edges of the hinged panel. They are not sufficiently supple to retain their initial position once they have been accidentally bent or used for a prolonged period of time. In addition, they provide no thermal barrier between inside and outside conditions. Furthermore, in view of the fact that only one strip of sheet metal is used, weather proofing is never perfect even in new installations. It is also known to use such thin foil weather strips made of plastic material secured by gluing but these have been found quite fragile and ill-adapted to resist cracking or breaking in cold climates particularly when icing occurs around the periphery of the hinged panel.
More complex weather stripping systems have been developed in recent years which are adapted primarily for use in association with doors and more particularly for use on the threshold of doors as can be found by a review of the following United States patents: U.S. Pat. No. 2,592,861 to Close dated Apr. 15, 1952, U.S. Pat. No. 3,504,456 to Frederick dated Apr. 7, 1970, U.S. Pat. No. 3,521,404 to Hager et al dated July 21, 1970, U.S. Pat. No. 3,672,424 to Brown dated June 27, 1972, U.S. Pat. No. 3,851,420 to Tibbetts dated Dec. 3, 1974, U.S. Pat. No. 3,854,246 to McAllister dated Dec. 17, 1974, U.S. Pat. No. 4,006,562 to Belanger et al dated Feb. 8, 1977, U.S. Pat. No. 4,255,902 to Ruff dated Mar. 17, 1981, U.S. Pat. No. b 4,310,991 to Seely dated Jan. 19, 1982. The sealing elements disclosed in these various patents are relatively complex and designed for use only in association with hinged doors where there is a considerable degree of latitude for adjustment upon installation and subsequently thereto, and wherein the opening force may be quite high and still be tolerable in view of the relatively large extent of the panel being weather proofed. However, these sealing means are hardly convenient for windows of the casement and awning type which is the primary object of the present invention.
A sealing element having certain similarities with the weather strip according to the present invention is disclosed in U.S. Pat. No. 3,276,167 to Bus et al dated Oct. 4, 1966. However, this sealing element, in spite of the fact that it presents two sealing members in strip form is nevertheless fondamentally different from that of the present invention as will become more apparent from the following description.
The primary object of the present invention is to provide an extremely simple weather strip which is convenient for use around the hinged panels of windows of the casement and awning type and which is also usable around door panels and which assures essentially perfect weather proofing coupled with good thermal installation between inside and outside conditions. It is also an object of the present invention to provide such a weather strip which is very easy to install and also to replace should it ever become necessary to do so, and which is cheap to manufacture and convenient to install on the periphery of the hinged panel of a window or door opening.
I have discovered that these objects can be obtained in accordance with this invention with the use of a weather strip made of two different thermoplastic materials one being relatively rigid as to be stable against contraction and stretching, and the other being relatively supple and flexible so as to produce a perfect seal with minimal resistance to opening of the panel from the fully closed position. The weather strip in accordance with this invention comprises a base portion made of the relatively rigid plastic material which base portion presents a horizontal bar, and two spaced apart thin wings supported to the opposite ends of the bar of the base, which wings are made of the more flexible and supple plastic material. The wings project upwardly from the upper surface of the base away from the lower surface of the base which comprises suitable anchoring means.
The wings are sufficiently long and spaced apart so as to define therebetween a volume of air which becomes totally confined when the panel is in the fully closed position. The entrapped air becomes an effective thermal barrier between the inside and the outside conditions. The free edges of the wings are sufficiently fine and flexible as to provide excellent weather proofing even in conditions where the gap around the panel of the window or door opening is not perfectly uniform. Preferably, the composite weather strip according to this invention is produced by co-extrusion of two compatible thermoplastic materials, and the resultant combination has sufficient rigidity and stability as a result of the relatively strong base portion but its wings are very supple whereby they can easily bend and fold when opening the window or door to which they are secured. Preferably, the base of the weather strip is T-shaped and the vertical leg thereof constitutes a gripping leg having suitable anchoring means for holding the weather strip by frictional engagement with a relatively deep groove extending continuously around the window or door panel, which continuous groove extends on the outside edges of such panel. Longitudinal ribs on the gripping leg of the weather strip constitutes a preferred form of anchoring means which has been found quite suitable and reliable.